Inkjet printers employing Memjet® technology are commercially available for a number of different printing formats, including small-office-home-office (“SOHO”) printers, label printers and wideformat printers. Memjet® printers typically comprise one or more stationary inkjet printheads, which are user-replaceable. For example, a SOHO printer comprises a single user-replaceable multi-colored printhead, a high-speed label printer comprises a plurality of user-replaceable monochrome printheads aligned along a media feed direction, and a wideformat printer comprises a plurality of user-replaceable printheads in a staggered overlapping arrangement so as to span across a wideformat pagewidth.
Supplying ink to multiple printheads can be problematic as the number of printheads increases. In order to maintain high print quality, each printhead should receive ink at about the same ink pressure from a common ink tank. One system for supplying ink to multiple inkjet printheads is described in U.S. Pat. No. 8,480,211, the contents of which are incorporate herein by reference. In the prior art system, a common accumulator tank incorporating a pressure control system (e.g. float valve regulator) feeds ink to multiple printheads via an ink supply line. A return ink line enables various priming, de-priming and purging operations when the printheads are not printing. However, a problem with the ink delivery system described in U.S. Pat. No. 8,480,211 is that not all printheads necessarily receive the same ink pressure. Printheads furthest from the accumulator tank are affected by pressure drops across printheads closer to the accumulator tank. Hence, there is a tendency for printheads to experience difference ink pressures, especially when printing at full bleed or when different printheads in the system have different ink demands.
It would be desirable to provide an ink delivery system, which supplies ink to multiple printheads at a reliable and highly controlled hydrostatic ink pressure. It would further be desirable to provide a scalable ink delivery system, which can be adapted to supply ink to multiple printheads, the number of which may vary from printing system to printing system.